Based on my experience R-134a is not more corrosive than the one (R22, or R12) it replaced. There is lots of equipment with R134a that is not failing just because the industry switched from one refrigerant to the other. But even if it were the case it is still no excuse to have short life evaporators installed. Volvo and other car manufacturers should use parts that will stand up to the environment. I don't think that any of us forced them to switch refrigerants. They did it on their own under government pressure to get into more environmentally friendly refrigerants (ozone hole) and if the new components weren't tested enough then they should fix them. Several years ago there was leaded gas available. One of the purposes for the lead was to lubricate valves, etc. When unleaded fuel got introduced valves and other components got redesigned to cope with the lack of lubrication provided by lead. I guess engines didn't suddenly started to seize and we didn't need to get the usual excuse.